The power capacity of semiconductor electronic devices is limited by temperature. Semiconductor electronic devices are destroyed when their internal temperature reaches a particular limit. The limit depends upon the nature of the electronic device. In order to increase the electrical capacity of such devices, they have to be cooled. The manner of cooling depends on the amount of power available for the cooling process. Different cooling fluids are used, depending on the application and depending on the density of the electronic devices. In some cases, finned cold plates carry the electronic devices and convection cooling by ambient air is sufficient to prevent overheating of the electronic devices. In other cases, liquids are used. In some cases, they are boiling liquids such as fluorinated hydrocarbon refrigerants, which are delivered to the cold plate in liquid form and are boiled therein to remove heat. Such systems perhaps have the highest heat removal rate for a limited cold plate area, but require a considerable amount of power to operate. In other systems, a cold liquid is circulated through the cold plate and the cold liquid may be refrigerator cooled, evaporatively cooled, or convectively cooled to the atmosphere. At relatively low pumping rates, with consequent low pumping power, a significant boundary layer builds on the various surfaces within the cold plate to reduce heat transfer rates. In an attempt to increase heat transfer, the mounting plate often carried fins thereon in order to increase interface area. However, as stated above, the velocity of the flow and, therefore, the forced convection heat transfer coefficient is controlled by the flow channel configuration. High liquid coolant velocities are achieved with small channels, but the fin and channel sizes are limited by manufacturing capabilities. Furthermore, high efficiency localized cooling was not possible in these structures because the coolant liquid must travel along the full length of the fins and the mounting plate. With the boundary layer built up over the large area, heat transfer was inhibited.